Bromine Cation Initiated vic-Diphosphination of Styrenes with Diphosphines under Photoredox Catalysis

Synthesis ◽  
2018 ◽  
Vol 50 (17) ◽  
pp. 3402-3407 ◽  
Author(s):  
Koji Hirano ◽  
Masahiro Miura ◽  
Nobutaka Otomura ◽  
Yuto Okugawa
Keyword(s):  
Visible Light ◽  
Functional Group ◽  
Single Electron ◽  
Photoredox Catalysis ◽  
Reaction Efficiency ◽  
Key Species ◽  
Electron Reduction

An N-bromosuccinimide (NBS)-initiated vic-diphosphination of styrenes with diphosphines proceeds under visible-light-promoted Ir(ppy)3 photoredox catalysis to deliver the corresponding 1,2-diphosphinoethane derivatives in good yields. The NBS is a bromine cation source and generates a bromophosphine, which undergoes a single-electron reduction by the excited iridium species to form phosphinyl radicals of key species in the diphoshination reaction. The newly developed photoredox catalysis demonstrates better reaction efficiency, functional group compatibility, and scalability than the previous photocatalysis using N-fluorobenzenesulfonimide (NFSI) and silylphosphine.

scholarly journals α-Functionalization of Imines via Visible Light Photoredox Catalysis

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 562 ◽  
Author(s):  
Alberto F. Garrido-Castro ◽  
M. Carmen Maestro ◽  
José Alemán
Keyword(s):  
Visible Light ◽  
Building Blocks ◽  
Single Electron ◽  
Synthetic Chemistry ◽  
Photoredox Catalysis ◽  
Reaction Conditions ◽  
Radical Intermediates ◽  
Research Programs ◽  
Electron Reduction

The innate electrophilicity of imine building blocks has been exploited in organic synthetic chemistry for decades. Inspired by the resurgence in photocatalysis, imine reactivity has now been redesigned through the generation of unconventional and versatile radical intermediates under mild reaction conditions. While novel photocatalytic approaches have broadened the range and applicability of conventional radical additions to imine acceptors, the possibility to use these imines as latent nucleophiles via single-electron reduction has also been uncovered. Thus, multiple research programs have converged on this issue, delivering creative and practical strategies to achieve racemic and asymmetric α-functionalizations of imines under visible light photoredox catalysis.

scholarly journals A Multiphoton Single-Electron Reduction of Olefins via Tandem Photoredox Catalysis

2020 ◽  
Author(s):  
Tyra Horngren ◽  
Mitchell S. Taylor ◽  
Milena Czyz ◽  
Anastasios Polyzos
Keyword(s):  
Visible Light ◽  
Radical Anion ◽  
Hydrogen Gas ◽  
Single Electron ◽  
Photoredox Catalysis ◽  
Reaction Conditions ◽  
Electron Reduction

<p><a></a>Herein we report a visible light multiphoton tandem photoredox catalysis strategy enabling a distinctive mode of olefin activation via a one electron reduction to the corresponding radical anion. This highly nucleophilic intermediate was harnessed to develop a method for the formal hydrogenation of unactivated alkenes under mild reaction conditions, in the absence of hydrogen gas or dissolving metals. <b></b></p>

A Multiphoton Single-Electron Reduction of Olefins via Tandem Photoredox Catalysis

2020 ◽  
Author(s):  
Tyra Horngren ◽  
Mitchell S. Taylor ◽  
Milena Czyz ◽  
Anastasios Polyzos
Keyword(s):  
Visible Light ◽  
Radical Anion ◽  
Hydrogen Gas ◽  
Single Electron ◽  
Photoredox Catalysis ◽  
Reaction Conditions ◽  
Electron Reduction

<p><a></a>Herein we report a visible light multiphoton tandem photoredox catalysis strategy enabling a distinctive mode of olefin activation via a one electron reduction to the corresponding radical anion. This highly nucleophilic intermediate was harnessed to develop a method for the formal hydrogenation of unactivated alkenes under mild reaction conditions, in the absence of hydrogen gas or dissolving metals. <b></b></p>

scholarly journals Combined Photoredox and Carbene Catalysis for the Synthesis of Ketones from Carboxylic Acids

2020 ◽  
Author(s):  
Anna Davies ◽  
keegan fitzpatrick ◽  
Rick Betori ◽  
Karl Scheidt
Keyword(s):  
Carboxylic Acids ◽  
Late Stage ◽  
Pharmaceutical Compounds ◽  
Single Electron ◽  
Photoredox Catalysis ◽  
Radical Coupling ◽  
Electron Reduction

Disclosed herein is the development of a novel single-electron reduction of acyl azoliums for the formation of ketones from carboxylic acids. Facile construction of the acyl azolium <i>in situ</i> followed by a radical-radical coupling was made possible using merged NHC-photoredox catalysis. The utility of this protocol in synthesis was demonstrated in the late-stage functionalization of a variety of pharmaceutical compounds.

Visible light mediated synthesis of 4-aryl-1,2-dihydronaphthalene derivatives via single-electron oxidation or MHAT from methylenecyclopropanes

2021 ◽  
Vol 8 (1) ◽  
pp. 94-100
Author(s):  
Jiaxin Liu ◽  
Yin Wei ◽  
Min Shi
Keyword(s):  
Visible Light ◽  
Single Electron ◽  
Photoredox Catalysis ◽  
Synthetic Strategy ◽  
Rapid Construction

A new synthetic strategy of a single-electron oxidation and MHAT of methylenecyclopropanes (MCPs) for the rapid construction of 4-aryl-1,2-dihydronaphthalene derivatives by merging photoredox catalysis and cobalt catalysis has been developed.

Visible Light Promoted Functionalisation of Carbon-Carbon Sigma Bonds

2019 ◽  
Author(s):  
Jeremy Nugent ◽  
Carlos Arroniz ◽  
Bethany Shire ◽  
Alistair J. Sterling ◽  
Helena D. Pickford ◽  
...  
Keyword(s):  
Visible Light ◽  
Organic Molecules ◽  
Functional Group ◽  
Single Step ◽  
Transition Metal Catalysts ◽  
Organic Radicals ◽  
Photoredox Catalysis ◽  
Halogen Bonds ◽  
Organic Halides ◽  
Pi Bonds

<p>The use of visible light to activate transition metal catalysts towards redox processes has transformed the way organic molecules can be constructed. Promotion of an electron to an excited state enables the generation of organic radicals through electron transfer to or from the metal complex, with the resulting radicals primed for reactions such as addition to carbon–carbon pi bonds. Despite advances in photoredox catalysis which have led to the discovery of numerous such methods for bond construction, this mild approach to the generation of free radicals has not been applied to the functionalisation of carbon–carbon sigma<i></i>bonds. Here we report the first such use of photoredox catalysis to promote the addition of organic halides to the caged carbocycle [1.1.1]propellane; the products of this process are bicyclo[1.1.1]pentanes (BCPs), motifs that are of high importance as bioisosteres in the pharmaceutical industry, and in materials applications. The methodology shows broad substrate scope and functional group tolerance, and is applicable to both <i>sp</i><sup>2</sup>and <i>sp</i><sup>3</sup>carbon–halogen bonds, while the use of substrates containing alkene acceptors enables the single-step construction of polycyclic bicyclopentane products through cyclisation cascades. Finally, the potential to accelerate drug discovery is demonstrated through examples of late-stage bicyclopentylation to access natural product- and drug-like molecules.</p>

scholarly journals Combined Photoredox and Carbene Catalysis for the Synthesis of Ketones from Carboxylic Acids

2020 ◽  
Author(s):  
Anna Davies ◽  
keegan fitzpatrick ◽  
Rick Betori ◽  
Karl Scheidt
Keyword(s):  
Carboxylic Acids ◽  
Late Stage ◽  
Pharmaceutical Compounds ◽  
Single Electron ◽  
Photoredox Catalysis ◽  
Radical Coupling ◽  
Electron Reduction

Disclosed herein is the development of a novel single-electron reduction of acyl azoliums for the formation of ketones from carboxylic acids. Facile construction of the acyl azolium <i>in situ</i> followed by a radical-radical coupling was made possible using merged NHC-photoredox catalysis. The utility of this protocol in synthesis was demonstrated in the late-stage functionalization of a variety of pharmaceutical compounds.

Visible Light Promoted Functionalisation of Carbon-Carbon Sigma Bonds

2019 ◽  
Author(s):  
Jeremy Nugent ◽  
Carlos Arroniz ◽  
Bethany Shire ◽  
Alistair J. Sterling ◽  
Helena D. Pickford ◽  
...  
Keyword(s):  
Visible Light ◽  
Organic Molecules ◽  
Functional Group ◽  
Single Step ◽  
Transition Metal Catalysts ◽  
Organic Radicals ◽  
Photoredox Catalysis ◽  
Halogen Bonds ◽  
Organic Halides ◽  
Pi Bonds

<p>The use of visible light to activate transition metal catalysts towards redox processes has transformed the way organic molecules can be constructed. Promotion of an electron to an excited state enables the generation of organic radicals through electron transfer to or from the metal complex, with the resulting radicals primed for reactions such as addition to carbon–carbon pi bonds. Despite advances in photoredox catalysis which have led to the discovery of numerous such methods for bond construction, this mild approach to the generation of free radicals has not been applied to the functionalisation of carbon–carbon sigma<i></i>bonds. Here we report the first such use of photoredox catalysis to promote the addition of organic halides to the caged carbocycle [1.1.1]propellane; the products of this process are bicyclo[1.1.1]pentanes (BCPs), motifs that are of high importance as bioisosteres in the pharmaceutical industry, and in materials applications. The methodology shows broad substrate scope and functional group tolerance, and is applicable to both <i>sp</i><sup>2</sup>and <i>sp</i><sup>3</sup>carbon–halogen bonds, while the use of substrates containing alkene acceptors enables the single-step construction of polycyclic bicyclopentane products through cyclisation cascades. Finally, the potential to accelerate drug discovery is demonstrated through examples of late-stage bicyclopentylation to access natural product- and drug-like molecules.</p>

A Single Electron Transfer (SET) Approach to C–H Amidation of Hydrazones via Visible-Light Photoredox Catalysis

2016 ◽  
Vol 18 (20) ◽  
pp. 5356-5359 ◽  
Author(s):  
Muliang Zhang ◽  
Yingqian Duan ◽  
Weipeng Li ◽  
Pan Xu ◽  
Jian Cheng ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Photoredox Catalysis

scholarly journals Polysulfide Anions as Visible Light Photoredox Catalysts for Aryl Cross-Couplings

2020 ◽  
Author(s):  
Haoyu Li ◽  
Xinxin Tang ◽  
Jia Hao Pang ◽  
Xiangyang Wu ◽  
Edwin K. L. Yeow ◽  
...  
Keyword(s):  
Visible Light ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Single Electron ◽  
Coupling Reactions ◽  
Aryl Radicals ◽  
Cross Coupling Reactions ◽  
Redox Couples ◽  
Electron Reduction

Herein, we disclose the use of polysulfide anions as visible light photoredox catalysts for aryl cross-coupling reactions. The reaction design enables single-electron-reduction of aryl halides upon photo-excitation of tetrasulfide dianions (S<sub>4</sub><sup>2–</sup>). The resulting aryl radicals are engaged in (hetero)biaryl cross-coupling, borylation, and hydrogenation in a redox catalytic regime involving S<sub>4</sub><sup>•–</sup>/S<sub>4</sub><sup>2–</sup> and S<sub>3</sub><sup>•–</sup>/S<sub>3</sub><sup>2–</sup> redox couples.

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